Study the mechanism of activation of adenylate cyclase by hormones and fluoride on the basis of the existence of the enzyme in a nonactivated phospho form and an activated dephospho form. Study the activation of phosphoprotein phosphatase by hormones and fluoride on the same basis as the cyclase. Study the nature of the activation of phosphoglucomutase in vivo by insulin. Study the mechanism of action of the phagocytosis stimulating tetrapeptide Thr-Lys-Pro-Arg-(tuftsin) as related to the motility and increased longevity of the phagocytes. Study the nature of the mutant peptide in human tuftsin deficiency syndrome. Study the nature of tuftsin deficiency after splenectomy and in patients with deficiency of splenic function as in sickle cell anemia and lukemias. Study the nature of the altered tuftsin receptor sites on the polymorphonuclear leucocytes in myelogenous leukemia.